Huge congratulations to IM. Landing on the Moon is extremely difficult, despite what playing KSP will condition you to think. For them to successfully land on the Moon is a huge milestone. Now to get people back there... maybe someday.
I still just cannot wrap my mind around how we could get people there, and then all this time later have lost that ability. What happened?
Another part is safety: Apollo was extremely dangerous. There were a lot of single points of failure, three astronauts died on the ground, three more were very very narrowly saved over the course of only about ten missions. One of the reasons the program was cut short was the political worry after Apollo 13 of having astronauts die on the moon or something similar. This level of danger was considered acceptable given the mission back then, but I don't think it would be today. Who's right is a worthwhile question.
Another part was that Apollo had superb, hard working, young, smart, energetic people working on it. The nature and ambition of the project just attracted top people. The context of the Vietnam war also meant that there were a lot of engineers that would otherwise be working on weapons but maybe would rather not, and Apollo was a very nice peaceful project to apply all of that technology to.
I think you see a lot of the success of Tesla and SpaceX in the same observations. Both of those companies were super ambitious, and had a goal a lot of people wanted to get behind. Their competition was unattractive to work for, and seemed unlikely to achieve the goal of getting to mars/electric cars. The result was that they were able to hire some of the very smartest, hardest working people in the country. If you get a bunch of people like that together under a common banner, amazing things happen.